package com.hezhiqin.netty.im.protocol;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import org.msgpack.MessagePack;
import org.msgpack.MessageTypeException;

import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @program: homeWork
 * @description: 自定义IM协议的解码器
 * @author: hezhiqin
 * @create: 2020-01-06 13:37
 */
public class IMDecoder extends ByteToMessageDecoder {

    //解析IM写一下请求内容的正则
    private Pattern pattern = Pattern.compile("^\\[(.*)\\](\\s\\-\\s(.*))?");


    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        try{
            //先获取可读字节数
            final int length = in.readableBytes();
            final byte[] array = new byte[length];
            String content = new String(array,in.readerIndex(),length);

            //空消息不解析
            if(!(null == content || "".equals(content.trim()))){
                if(!IMP.isIMP(content)){
                    ctx.channel().pipeline().remove(this);
                    return;
                }
            }

            in.getBytes(in.readerIndex(), array, 0, length);
            out.add(new MessagePack().read(array,IMMessage.class));
            in.clear();
        }catch(MessageTypeException e){
            ctx.channel().pipeline().remove(this);
        }
    }


    /**
     * 字符串解析成自定义即时通信协议
     * @param msg
     * @return
     */
    public IMMessage decode(String msg){
        if(null == msg || "".equals(msg.trim())){ return null; }
        try{
            Matcher m = pattern.matcher(msg);
            String header = "";
            String content = "";
            if(m.matches()){
                header = m.group(1);
                content = m.group(3);
            }

            String [] heards = header.split("\\]\\[");
            long time = 0;
            try{ time = Long.parseLong(heards[1]); } catch(Exception e){}
            String nickName = heards[2];
            //昵称最多十个字
            nickName = nickName.length() < 10 ? nickName : nickName.substring(0, 9);

            if(msg.startsWith("[" + IMP.LOGIN.getName() + "]")){
                return new IMMessage(heards[0],heards[3],time,nickName);
            }else if(msg.startsWith("[" + IMP.CHAT.getName() + "]")){
                return new IMMessage(heards[0],time,nickName,content);
            }else if(msg.startsWith("[" + IMP.FLOWER.getName() + "]")){
                return new IMMessage(heards[0],heards[3],time,nickName);
            }else{
                return null;
            }
        }catch(Exception e){
            e.printStackTrace();
            return null;
        }
    }

}
